This may happen only when you are trying to set the timer clock at night on the last day of the month. Please try setting the timer clock again 24 hours later.
You may need to re-synchronize the internal clock of your device with your computer. Please first backup all the contents in your device onto your computer and then use your computer to format the device. After formatting unplug and reconnect the device with your computer and then download the music again then the device will re-synchronize its internal clock automatically.